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Fong JK, Mathieu Y, Vo MT, Bellemare A, Tsang A, Brumer H. Expansion of Auxiliary Activity Family 5 sequence space via biochemical characterization of six new copper radical oxidases. Appl Environ Microbiol 2024; 90:e0101424. [PMID: 38953370 PMCID: PMC11267884 DOI: 10.1128/aem.01014-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2024] [Accepted: 06/14/2024] [Indexed: 07/04/2024] Open
Abstract
Bacterial and fungal copper radical oxidases (CROs) from Auxiliary Activity Family 5 (AA5) are implicated in morphogenesis and pathogenesis. The unique catalytic properties of CROs also make these enzymes attractive biocatalysts for the transformation of small molecules and biopolymers. Despite a recent increase in the number of characterized AA5 members, especially from subfamily 2 (AA5_2), the catalytic diversity of the family as a whole remains underexplored. In the present study, phylogenetic analysis guided the selection of six AA5_2 members from diverse fungi for recombinant expression in Komagataella pfaffii (syn. Pichia pastoris) and biochemical characterization in vitro. Five of the targets displayed predominant galactose 6-oxidase activity (EC 1.1.3.9), and one was a broad-specificity aryl alcohol oxidase (EC 1.1.3.7) with maximum activity on the platform chemical 5-hydroxymethyl furfural (EC 1.1.3.47). Sequence alignment comparing previously characterized AA5_2 members to those from this study indicated various amino acid substitutions at active site positions implicated in the modulation of specificity.IMPORTANCEEnzyme discovery and characterization underpin advances in microbial biology and the application of biocatalysts in industrial processes. On one hand, oxidative processes are central to fungal saprotrophy and pathogenesis. On the other hand, controlled oxidation of small molecules and (bio)polymers valorizes these compounds and introduces versatile functional groups for further modification. The biochemical characterization of six new copper radical oxidases further illuminates the catalytic diversity of these enzymes, which will inform future biological studies and biotechnological applications.
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Affiliation(s)
- Jessica K. Fong
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada
| | - Yann Mathieu
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
| | - Minh Tri Vo
- Centre for Structural and Functional Genomics, Concordia University, Montreal, Quebec, Canada
| | - Annie Bellemare
- Centre for Structural and Functional Genomics, Concordia University, Montreal, Quebec, Canada
| | - Adrian Tsang
- Centre for Structural and Functional Genomics, Concordia University, Montreal, Quebec, Canada
| | - Harry Brumer
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada
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2
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Schober L, Dobiašová H, Jurkaš V, Parmeggiani F, Rudroff F, Winkler M. Enzymatic reactions towards aldehydes: An overview. FLAVOUR FRAG J 2023; 38:221-242. [PMID: 38505272 PMCID: PMC10947199 DOI: 10.1002/ffj.3739] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 03/01/2023] [Accepted: 03/06/2023] [Indexed: 03/21/2024]
Abstract
Many aldehydes are volatile compounds with distinct and characteristic olfactory properties. The aldehydic functional group is reactive and, as such, an invaluable chemical multi-tool to make all sorts of products. Owing to the reactivity, the selective synthesis of aldehydic is a challenging task. Nature has evolved a number of enzymatic reactions to produce aldehydes, and this review provides an overview of aldehyde-forming reactions in biological systems and beyond. Whereas some of these biotransformations are still in their infancy in terms of synthetic applicability, others are developed to an extent that allows their implementation as industrial biocatalysts.
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Affiliation(s)
- Lukas Schober
- Institute of Molecular BiotechnologyGraz University of TechnologyGrazAustria
| | - Hana Dobiašová
- Institute of Chemical and Environmental EngineeringSlovak University of TechnologyBratislavaSlovakia
| | - Valentina Jurkaš
- Institute of Molecular BiotechnologyGraz University of TechnologyGrazAustria
| | - Fabio Parmeggiani
- Dipartimento di Chimica, Materiali ed Ingegneria Chimica “Giulio Natta”Politecnico di MilanoMilanItaly
| | - Florian Rudroff
- Institute of Applied Synthetic ChemistryTU WienViennaAustria
| | - Margit Winkler
- Institute of Molecular BiotechnologyGraz University of TechnologyGrazAustria
- Area BiotransformationsAustrian Center of Industrial BiotechnologyGrazAustria
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3
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Copper radical oxidases: galactose oxidase, glyoxal oxidase, and beyond! Essays Biochem 2022; 67:597-613. [PMID: 36562172 DOI: 10.1042/ebc20220124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 10/14/2022] [Accepted: 11/23/2022] [Indexed: 12/24/2022]
Abstract
The copper radical oxidases (CROs) are an evolutionary and functionally diverse group of enzymes established by the historically significant galactose 6-oxidase and glyoxal oxidase from fungi. Inducted in 2013, CROs now constitute Auxiliary Activity Family 5 (AA5) in the Carbohydrate-Active Enzymes (CAZy) classification. CROs catalyse the two-electron oxidation of their substrates using oxygen as the final electron acceptor and are particularly distinguished by a cross-linked tyrosine-cysteine co-factor that is integral to radical stabilization. Recently, there has been a significant increase in the biochemically and structurally characterized CROs, which has revealed an expanded natural diversity of catalytic activities in the family. This review provides a brief historical introduction to CRO biochemistry and structural biology as a foundation for an update on current advances in CRO enzymology, biotechnology, and biology across kingdoms of life.
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4
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Yeow K, Haarr MB, Muldoon J, O'Reilly E. Preparation of iminosugars from aminopolyols via selective oxidation using galactose oxidase. Chem Commun (Camb) 2022; 58:13640-13643. [PMID: 36409216 DOI: 10.1039/d2cc04989a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Minimally protected aminopolyols are novel substrates for the galactose oxidase variant F2. Site-selective oxidation proceeds at the terminal primary alcohol, followed by spontaneous cyclisation to afford stable hemiaminal/hemiacetal anomers of the piperidine and azepane scaffolds, with isolated yields of up to 94%. Simultaneous deprotection and reduction occured readily to afford valuable and biologically relevant iminosugars.
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Affiliation(s)
- Kathryn Yeow
- School of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland.
| | - Marianne B Haarr
- School of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland.
| | - Jimmy Muldoon
- Mass Spectrometry Facility, School of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland
| | - Elaine O'Reilly
- School of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland.
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5
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Concha D, Rodríguez-Núñez K, Castillo L, Martínez R, Bernal C. Galactaric acid production by engineering substrate specificity in glucose oxidase from Aspergillus niger. Biochem Eng J 2022. [DOI: 10.1016/j.bej.2022.108646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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6
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Mathieu Y, Cleveland ME, Brumer H. Active-Site Engineering Switches Carbohydrate Regiospecificity in a Fungal Copper Radical Oxidase. ACS Catal 2022; 12:10264-10275. [PMID: 36033369 PMCID: PMC9397409 DOI: 10.1021/acscatal.2c01956] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 06/15/2022] [Indexed: 11/30/2022]
Abstract
Copper radical oxidases (CROs) from Auxiliary Activity Family 5, Subfamily 2 (AA5_2), are organic cofactor-free biocatalysts for the selective oxidation of alcohols to the corresponding aldehydes. AA5_2 CROs comprise canonical galactose-6-oxidases as well as the more recently discovered general alcohol oxidases and aryl alcohol oxidases. Guided by primary and tertiary protein structural analyses, we targeted a distinct extended loop in the active site of a Colletotrichum graminicola aryl alcohol oxidase (CgrAAO) to explore its effect on catalysis in the broader context of AA5_2. Deletion of this loop, which is bracketed by a conserved disulfide bridge, significantly reduced the inherent activity of the enzyme toward extended galacto-oligosaccharides, as anticipated from molecular modeling. Unexpectedly, kinetic and product analysis on a range of monosaccharides and disaccharides revealed that an altered carbohydrate specificity in CgrAAO-Δloop was accompanied by a complete change in regiospecificity from C-6 to C-1 oxidation, thereby generating aldonic acids. C-1 regiospecificity is unprecedented in AA5 enzymes and is classically associated with flavin-dependent carbohydrate oxidases of Auxiliary Activity Family 3. Thus, this work further highlights the catalytic adaptability of the unique mononuclear copper radical active site and provides a basis for the design of improved biocatalysts for diverse potential applications.
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Affiliation(s)
- Yann Mathieu
- Michael
Smith Laboratories, University of British
Columbia, 2185 East Mall, Vancouver, British Columbia V6T 1Z4, Canada
- BioProducts
Institute, University of British Columbia, 2385 East Mall, Vancouver, British Columbia V6T 1Z4, Canada
| | - Maria E. Cleveland
- Michael
Smith Laboratories, University of British
Columbia, 2185 East Mall, Vancouver, British Columbia V6T 1Z4, Canada
- Department
of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
- BioProducts
Institute, University of British Columbia, 2385 East Mall, Vancouver, British Columbia V6T 1Z4, Canada
| | - Harry Brumer
- Michael
Smith Laboratories, University of British
Columbia, 2185 East Mall, Vancouver, British Columbia V6T 1Z4, Canada
- Department
of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
- BioProducts
Institute, University of British Columbia, 2385 East Mall, Vancouver, British Columbia V6T 1Z4, Canada
- Department
of Biochemistry and Molecular Biology, University
of British Columbia, 2350 Health Sciences Mall, Vancouver, British Columbia V6T 1Z3, Canada
- Department
of Botany, University of British Columbia, 3200 University Boulevard, Vancouver, British Columbia V6T 1Z4, Canada
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7
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Ribeaucourt D, Höfler GT, Yemloul M, Bissaro B, Lambert F, Berrin JG, Lafond M, Paul CE. Tunable Production of ( R)- or ( S)-Citronellal from Geraniol via a Bienzymatic Cascade Using a Copper Radical Alcohol Oxidase and Old Yellow Enzyme. ACS Catal 2022; 12:1111-1116. [PMID: 35096467 PMCID: PMC8787751 DOI: 10.1021/acscatal.1c05334] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 12/26/2021] [Indexed: 01/08/2023]
Abstract
Biocatalytic pathways for the synthesis of (-)-menthol, the most sold flavor worldwide, are highly sought-after. To access the key intermediate (R)-citronellal used in current major industrial production routes, we established a one-pot bienzymatic cascade from inexpensive geraniol, overcoming the problematic biocatalytic reduction of the mixture of (E/Z)-isomers in citral by harnessing a copper radical oxidase (CgrAlcOx) and an old yellow enzyme (OYE). The cascade using OYE2 delivered 95.1% conversion to (R)-citronellal with 95.9% ee, a 62 mg scale-up affording high yield and similar optical purity. An alternative OYE, GluER, gave (S)-citronellal from geraniol with 95.3% conversion and 99.2% ee.
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Affiliation(s)
- David Ribeaucourt
- INRAE, Aix Marseille Univ, UMR1163 Biodiversité et Biotechnologie Fongiques, 13009 Marseille, France
- Aix Marseille Univ, CNRS, Centrale Marseille, iSm2, 13013 Marseille, France
- V. Mane Fils, 620 route de Grasse, 06620 Le Bar sur Loup, France
| | - Georg T. Höfler
- Biocatalysis, Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Mehdi Yemloul
- Aix Marseille Univ, CNRS, Centrale Marseille, iSm2, 13013 Marseille, France
| | - Bastien Bissaro
- INRAE, Aix Marseille Univ, UMR1163 Biodiversité et Biotechnologie Fongiques, 13009 Marseille, France
| | - Fanny Lambert
- V. Mane Fils, 620 route de Grasse, 06620 Le Bar sur Loup, France
| | - Jean-Guy Berrin
- INRAE, Aix Marseille Univ, UMR1163 Biodiversité et Biotechnologie Fongiques, 13009 Marseille, France
| | - Mickael Lafond
- Aix Marseille Univ, CNRS, Centrale Marseille, iSm2, 13013 Marseille, France
| | - Caroline E. Paul
- Biocatalysis, Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
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8
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Kaddouch E, Cleveland ME, Navarro D, Grisel S, Haon M, Brumer H, Lafond M, Berrin JG, Bissaro B. A simple and direct ionic chromatography method to monitor galactose oxidase activity. RSC Adv 2022; 12:26042-26050. [PMID: 36199594 PMCID: PMC9469488 DOI: 10.1039/d2ra04485d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 09/06/2022] [Indexed: 11/21/2022] Open
Abstract
Galactose oxidase (GalOx, EC.1.1.3.9) is one of the most extensively studied copper radical oxidases (CROs). The reaction catalyzed by GalOx leads to the oxidation of the C-6 hydroxyl group of galactose and galactosides (including galactosylated polysaccharides and glycoproteins) to the corresponding aldehydes, coupled to the reduction of dioxygen to hydrogen peroxide. Despite more than 60 years of research including mechanistic studies, enzyme engineering and application development, GalOx activity remains primarily monitored by indirect measurement of the co-product hydrogen peroxide. Here, we describe a simple direct method to measure GalOx activity through the identification of galactosylated oxidized products using high-performance anion-exchange chromatography coupled to pulsed amperometric detection (HPAEC-PAD). Using galactose and lactose as representative substrates, we were able to separate and detect the C-6 oxidized products, which were confirmed by LC-MS and NMR analyses to exist in their hydrated (geminal-diol) forms. We show that the HPAEC-PAD method is superior to other methods in terms of sensitivity as we could detect down to 0.08 μM of LacOX (eq. 30 μg L−1). We believe the method will prove useful for qualitative detection of galactose oxidase activity in biological samples or for quantitative purposes to analyze enzyme kinetics or to compare enzyme variants in directed evolution programs. Galactose oxidase (GalOx, EC.1.1.3.9) is one of the most extensively studied copper radical oxidases. Here, we show it can be monitored through the release of oxidized galactosylated products using a simple, direct and sensitive HPAEC-PAD method.![]()
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Affiliation(s)
- Eden Kaddouch
- INRAE, Aix Marseille Université, UMR1163 Biodiversité et Biotechnologie Fongiques, 13009, Marseille, France
| | - Maria E. Cleveland
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, BC, V6T 1Z4, Canada
| | - David Navarro
- INRAE, Aix Marseille Université, UMR1163 Biodiversité et Biotechnologie Fongiques, 13009, Marseille, France
- INRAE, Aix Marseille Université, CIRM-CF, Marseille, France
| | - Sacha Grisel
- INRAE, Aix Marseille Université, UMR1163 Biodiversité et Biotechnologie Fongiques, 13009, Marseille, France
- INRAE, Aix Marseille Université, 3PE platform, Marseille, France
| | - Mireille Haon
- INRAE, Aix Marseille Université, UMR1163 Biodiversité et Biotechnologie Fongiques, 13009, Marseille, France
- INRAE, Aix Marseille Université, 3PE platform, Marseille, France
| | - Harry Brumer
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Mickaël Lafond
- Aix Marseille Université, CNRS, Centrale Marseille, iSm2, Marseille, France
| | - Jean-Guy Berrin
- INRAE, Aix Marseille Université, UMR1163 Biodiversité et Biotechnologie Fongiques, 13009, Marseille, France
- INRAE, Aix Marseille Université, 3PE platform, Marseille, France
| | - Bastien Bissaro
- INRAE, Aix Marseille Université, UMR1163 Biodiversité et Biotechnologie Fongiques, 13009, Marseille, France
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9
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Šola K, Dean GH, Li Y, Lohmann J, Movahedan M, Gilchrist EJ, Adams KL, Haughn GW. Expression Patterns and Functional Characterization of Arabidopsis Galactose Oxidase-Like Genes Suggest Specialized Roles for Galactose Oxidases in Plants. PLANT & CELL PHYSIOLOGY 2021; 62:1927-1943. [PMID: 34042158 DOI: 10.1093/pcp/pcab073] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 03/10/2021] [Accepted: 05/26/2021] [Indexed: 06/12/2023]
Abstract
Galactose oxidases (GalOxs) are well-known enzymes that have been identified in several fungal species and characterized using structural and enzymatic approaches. However, until very recently, almost no information on their biological functions was available. The Arabidopsis (Arabidopsis thaliana) gene ruby particles in mucilage (RUBY) encodes a putative plant GalOx that is required for pectin cross-linking through modification of galactose (Gal) side chains and promotes cell-cell adhesion between seed coat epidermal cells. RUBY is one member of a family of seven putative GalOxs encoded in the Arabidopsis genome. To examine the function(s) of GalOxs in plants, we studied the remaining six galactose oxidase-like (GOXL) proteins. Like RUBY, four of these proteins (GOXL1, GOXL3, GOXL5 and GOXL6) were found to localize primarily to the apoplast, while GOXL2 and GOXL4 were found primarily in the cytoplasm. Complementation and GalOx assay data suggested that GOXL1, GOXL3 and possibly GOXL6 have similar biochemical activity to RUBY, whereas GOXL5 only weakly complemented and GOXL2 and GOXL4 showed no activity. Members of this protein family separated into four distinct clades prior to the divergence of the angiosperms. There have been recent duplications in Brassicaceae resulting in two closely related pairs of genes that have either retained similarity in expression (GOXL1 and GOXL6) or show expression divergence (GOXL3 and RUBY). Mutant phenotypes were not detected when these genes were disrupted, but their expression patterns suggest that these proteins may function in tissues that require mechanical reinforcements in the absence of lignification.
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Affiliation(s)
- Krešimir Šola
- Department of Botany, University of British Columbia, 6270 University Blvd., Vancouver, British Columbia V6T 1Z4, Canada
- Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, Amsterdam, Noord-Holland 1098 XH, The Netherlands
| | - Gillian H Dean
- Department of Botany, University of British Columbia, 6270 University Blvd., Vancouver, British Columbia V6T 1Z4, Canada
| | - Yi Li
- Department of Botany, University of British Columbia, 6270 University Blvd., Vancouver, British Columbia V6T 1Z4, Canada
- Sjaak van Schie B.V., Maasdijk, Schenkeldijk 8, Zuid-Holland 2676 LD, The Netherlands
| | - Julia Lohmann
- Department of Botany, University of British Columbia, 6270 University Blvd., Vancouver, British Columbia V6T 1Z4, Canada
- Molecular Plant Physiology, Institute for Plant Science and Microbiology, Universität Hamburg, Ohnhorststr. 18, Hamburg 22609, Germany
| | - Mahsa Movahedan
- Department of Botany, University of British Columbia, 6270 University Blvd., Vancouver, British Columbia V6T 1Z4, Canada
- Burnaby Hospital, 3935 Kincaid St, Burnaby, British Columbia V5G 2X6, Canada
| | - Erin J Gilchrist
- Department of Botany, University of British Columbia, 6270 University Blvd., Vancouver, British Columbia V6T 1Z4, Canada
- Anandia Labs, 125-887 Great Northern Way, Vancouver, British Columbia V5T 4T5, Canada
| | - Keith L Adams
- Department of Botany, University of British Columbia, 6270 University Blvd., Vancouver, British Columbia V6T 1Z4, Canada
| | - George W Haughn
- Department of Botany, University of British Columbia, 6270 University Blvd., Vancouver, British Columbia V6T 1Z4, Canada
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10
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Cleveland ME, Mathieu Y, Ribeaucourt D, Haon M, Mulyk P, Hein JE, Lafond M, Berrin JG, Brumer H. A survey of substrate specificity among Auxiliary Activity Family 5 copper radical oxidases. Cell Mol Life Sci 2021; 78:8187-8208. [PMID: 34738149 PMCID: PMC11072238 DOI: 10.1007/s00018-021-03981-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 09/13/2021] [Accepted: 10/13/2021] [Indexed: 12/21/2022]
Abstract
There is significant contemporary interest in the application of enzymes to replace or augment chemical reagents toward the development of more environmentally sound and sustainable processes. In particular, copper radical oxidases (CRO) from Auxiliary Activity Family 5 Subfamily 2 (AA5_2) are attractive, organic cofactor-free catalysts for the chemoselective oxidation of alcohols to the corresponding aldehydes. These enzymes were first defined by the archetypal galactose-6-oxidase (GalOx, EC 1.1.3.13) from the fungus Fusarium graminearum. The recent discovery of specific alcohol oxidases (EC 1.1.3.7) and aryl alcohol oxidases (EC 1.1.3.47) within AA5_2 has indicated a potentially broad substrate scope among fungal CROs. However, only relatively few AA5_2 members have been characterized to date. Guided by sequence similarity network and phylogenetic analysis, twelve AA5_2 homologs have been recombinantly produced and biochemically characterized in the present study. As defined by their predominant activities, these comprise four galactose 6-oxidases, two raffinose oxidases, four broad-specificity primary alcohol oxidases, and two non-carbohydrate alcohol oxidases. Of particular relevance to applications in biomass valorization, detailed product analysis revealed that two CROs produce the bioplastics monomer furan-2,5-dicarboxylic acid (FDCA) directly from 5-hydroxymethylfurfural (HMF). Furthermore, several CROs could desymmetrize glycerol (a by-product of the biodiesel industry) to D- or L-glyceraldehyde. This study furthers our understanding of CROs by doubling the number of characterized AA5_2 members, which may find future applications as biocatalysts in diverse processes.
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Affiliation(s)
- Maria E Cleveland
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, BC, V6T 1Z4, Canada
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC, V6T 1Z1, Canada
- BioProducts Institute, University of British Columbia, 2385 East Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Yann Mathieu
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, BC, V6T 1Z4, Canada
- BioProducts Institute, University of British Columbia, 2385 East Mall, Vancouver, BC, V6T 1Z4, Canada
| | - David Ribeaucourt
- INRAE, Aix Marseille Univ, UMR 1163 Biodiversité et Biotechnologie Fongiques, 13009, Marseille, France
- Aix Marseille Univ, CNRS, Centrale Marseille, iSm2, Marseille, France
- V. Mane Fils, 620 route de Grasse, 06620, Le Bar sur Loup, France
| | - Mireille Haon
- INRAE, Aix Marseille Univ, UMR 1163 Biodiversité et Biotechnologie Fongiques, 13009, Marseille, France
| | - Paul Mulyk
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC, V6T 1Z1, Canada
| | - Jason E Hein
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC, V6T 1Z1, Canada
| | - Mickael Lafond
- Aix Marseille Univ, CNRS, Centrale Marseille, iSm2, Marseille, France
| | - Jean-Guy Berrin
- INRAE, Aix Marseille Univ, UMR 1163 Biodiversité et Biotechnologie Fongiques, 13009, Marseille, France
| | - Harry Brumer
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, BC, V6T 1Z4, Canada.
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC, V6T 1Z1, Canada.
- BioProducts Institute, University of British Columbia, 2385 East Mall, Vancouver, BC, V6T 1Z4, Canada.
- Department of Biochemistry and Molecular Biology, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada.
- Department of Botany, University of British Columbia, 3200 University Boulevard, Vancouver, BC, V6T 1Z4, Canada.
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11
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Figueiredo C, De Lacey AL, Pita M. Electrochemical studies of galactose oxidase. ELECTROCHEMICAL SCIENCE ADVANCES 2021. [DOI: 10.1002/elsa.202100171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
| | | | - Marcos Pita
- Instituto de Catálisis y Petroleoquímica CSIC Madrid Spain
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12
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Ribeaucourt D, Bissaro B, Lambert F, Lafond M, Berrin JG. Biocatalytic oxidation of fatty alcohols into aldehydes for the flavors and fragrances industry. Biotechnol Adv 2021; 56:107787. [PMID: 34147589 DOI: 10.1016/j.biotechadv.2021.107787] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 06/13/2021] [Accepted: 06/15/2021] [Indexed: 01/11/2023]
Abstract
From Egyptian mummies to the Chanel n°5 perfume, fatty aldehydes have long been used and keep impacting our senses in a wide range of foods, beverages and perfumes. Natural sources of fatty aldehydes are threatened by qualitative and quantitative variability while traditional chemical routes are insufficient to answer the society shift toward more sustainable and natural products. The production of fatty aldehydes using biotechnologies is therefore the most promising alternative for the flavors and fragrances industry. In this review, after drawing the portrait of the origin and characteristics of fragrant fatty aldehydes, we present the three main classes of enzymes that catalyze the reaction of fatty alcohols oxidation into aldehydes, namely alcohol dehydrogenases, flavin-dependent alcohol oxidases and copper radical alcohol oxidases. The constraints, challenges and opportunities to implement these oxidative enzymes in the flavors and fragrances industry are then discussed. By setting the scene on the biocatalytic production of fatty aldehydes, and providing a critical assessment of its potential, we expect this review to contribute to the development of biotechnology-based solutions in the flavors and fragrances industry.
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Affiliation(s)
- David Ribeaucourt
- INRAE, Aix Marseille Univ, UMR1163 Biodiversité et Biotechnologie Fongiques, 13009 Marseille, France; V. Mane Fils, 620 route de Grasse, 06620 Le Bar sur Loup, France; Aix Marseille Univ, CNRS, Centrale Marseille, iSm2, Marseille, France.
| | - Bastien Bissaro
- INRAE, Aix Marseille Univ, UMR1163 Biodiversité et Biotechnologie Fongiques, 13009 Marseille, France
| | - Fanny Lambert
- V. Mane Fils, 620 route de Grasse, 06620 Le Bar sur Loup, France
| | - Mickael Lafond
- Aix Marseille Univ, CNRS, Centrale Marseille, iSm2, Marseille, France
| | - Jean-Guy Berrin
- INRAE, Aix Marseille Univ, UMR1163 Biodiversité et Biotechnologie Fongiques, 13009 Marseille, France.
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13
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Cleveland M, Lafond M, Xia FR, Chung R, Mulyk P, Hein JE, Brumer H. Two Fusarium copper radical oxidases with high activity on aryl alcohols. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:138. [PMID: 34134727 PMCID: PMC8207647 DOI: 10.1186/s13068-021-01984-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Accepted: 06/03/2021] [Indexed: 06/12/2023]
Abstract
BACKGROUND Biomass valorization has been suggested as a sustainable alternative to petroleum-based energy and commodities. In this context, the copper radical oxidases (CROs) from Auxiliary Activity Family 5/Subfamily 2 (AA5_2) are attractive biocatalysts for the selective oxidation of primary alcohols to aldehydes. Originally defined by the archetypal galactose 6-oxidase from Fusarium graminearum, fungal AA5_2 members have recently been shown to comprise a wide range of specificities for aromatic, aliphatic and furan-based alcohols. This suggests a broader substrate scope of native CROs for applications. However, only 10% of the annotated AA5_2 members have been characterized to date. RESULTS Here, we define two homologues from the filamentous fungi Fusarium graminearum and F. oxysporum as predominant aryl alcohol oxidases (AAOs) through recombinant production in Pichia pastoris, detailed kinetic characterization, and enzyme product analysis. Despite possessing generally similar active-site architectures to the archetypal FgrGalOx, FgrAAO and FoxAAO have weak activity on carbohydrates, but instead efficiently oxidize specific aryl alcohols. Notably, both FgrAAO and FoxAAO oxidize hydroxymethyl furfural (HMF) directly to 5-formyl-2-furoic acid (FFCA), and desymmetrize the bioproduct glycerol to the uncommon L-isomer of glyceraldehyde. CONCLUSIONS This work expands understanding of the catalytic diversity of CRO from AA5_2 to include unique representatives from Fusarium species that depart from the well-known galactose 6-oxidase activity of this family. Detailed enzymological analysis highlights the potential biotechnological applications of these orthologs in the production of renewable plastic polymer precursors and other chemicals.
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Affiliation(s)
- Maria Cleveland
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, BC, V6T 1Z4, Canada
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC, V6T 1Z1, Canada
- BioProducts Institute, University of British Columbia, 2385 East Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Mickael Lafond
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, BC, V6T 1Z4, Canada
- Aix Marseille Univ, CNRS, Centrale Marseille, iSm2, Marseille, France
| | - Fan Roderick Xia
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, BC, V6T 1Z4, Canada
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC, V6T 1Z1, Canada
- BioProducts Institute, University of British Columbia, 2385 East Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Ryan Chung
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC, V6T 1Z1, Canada
| | - Paul Mulyk
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC, V6T 1Z1, Canada
| | - Jason E Hein
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC, V6T 1Z1, Canada
| | - Harry Brumer
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, BC, V6T 1Z4, Canada.
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC, V6T 1Z1, Canada.
- BioProducts Institute, University of British Columbia, 2385 East Mall, Vancouver, BC, V6T 1Z4, Canada.
- Department of Biochemistry and Molecular Biology, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada.
- Department of Botany, University of British Columbia, 3200 University Boulevard, Vancouver, BC, V6T 1Z4, Canada.
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14
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Savino S, Fraaije MW. The vast repertoire of carbohydrate oxidases: An overview. Biotechnol Adv 2020; 51:107634. [PMID: 32961251 DOI: 10.1016/j.biotechadv.2020.107634] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 08/12/2020] [Accepted: 09/06/2020] [Indexed: 01/01/2023]
Abstract
Carbohydrates are widely abundant molecules present in a variety of forms. For their biosynthesis and modification, nature has evolved a plethora of carbohydrate-acting enzymes. Many of these enzymes are of particular interest for biotechnological applications, where they can be used as biocatalysts or biosensors. Among the enzymes catalysing conversions of carbohydrates are the carbohydrate oxidases. These oxidative enzymes belong to different structural families and use different cofactors to perform the oxidation reaction of CH-OH bonds in carbohydrates. The variety of carbohydrate oxidases available in nature reflects their specificity towards different sugars and selectivity of the oxidation site. Thanks to their properties, carbohydrate oxidases have received a lot of attention in basic and applied research, such that nowadays their role in biotechnological processes is of paramount importance. In this review we provide an overview of the available knowledge concerning the known carbohydrate oxidases. The oxidases are first classified according to their structural features. After a description on their mechanism of action, substrate acceptance and characterisation, we report on the engineering of the different carbohydrate oxidases to enhance their employment in biocatalysis and biotechnology. In the last part of the review we highlight some practical applications for which such enzymes have been exploited.
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Affiliation(s)
- Simone Savino
- Molecular Enzymology Group, University of Groningen, Nijenborgh 4, 9747AG Groningen, the Netherlands
| | - Marco W Fraaije
- Molecular Enzymology Group, University of Groningen, Nijenborgh 4, 9747AG Groningen, the Netherlands.
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15
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Mathieu Y, Offen WA, Forget SM, Ciano L, Viborg AH, Blagova E, Henrissat B, Walton PH, Davies GJ, Brumer H. Discovery of a Fungal Copper Radical Oxidase with High Catalytic Efficiency toward 5-Hydroxymethylfurfural and Benzyl Alcohols for Bioprocessing. ACS Catal 2020. [DOI: 10.1021/acscatal.9b04727] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Yann Mathieu
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, British Columbia V6T 1Z4, Canada
| | - Wendy A. Offen
- Department of Chemistry, University of York, Heslington, YO10 5DD, York, U.K
| | - Stephanie M. Forget
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, British Columbia V6T 1Z4, Canada
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Luisa Ciano
- Department of Chemistry, University of York, Heslington, YO10 5DD, York, U.K
| | - Alexander Holm Viborg
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, British Columbia V6T 1Z4, Canada
| | - Elena Blagova
- Department of Chemistry, University of York, Heslington, YO10 5DD, York, U.K
| | - Bernard Henrissat
- Architecture et Fonction des Macromolécules Biologiques (AFMB), CNRS, Aix-Marseille University, Marseille, 13288, France
- INRA, USC1408 Architecture et Fonction des Macromolécules Biologiques (AFMB), Marseille, 13288, France
| | - Paul H. Walton
- Department of Chemistry, University of York, Heslington, YO10 5DD, York, U.K
| | - Gideon J. Davies
- Department of Chemistry, University of York, Heslington, YO10 5DD, York, U.K
| | - Harry Brumer
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, British Columbia V6T 1Z4, Canada
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
- Department of Biochemistry and Molecular Biology, University of British Columbia, 2350 Health Sciences Mall, Vancouver, British Columbia V6T 1Z3, Canada
- Department of Botany, University of British Columbia, 3200 University Boulevard, Vancouver, British Columbia V6T 1Z4, Canada
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16
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Mattey AP, Birmingham WR, Both P, Kress N, Huang K, van Munster JM, Bulmer GS, Parmeggiani F, Voglmeir J, Martinez JER, Turner NJ, Flitsch SL. Selective Oxidation of N-Glycolylneuraminic Acid Using an Engineered Galactose Oxidase Variant. ACS Catal 2019. [DOI: 10.1021/acscatal.9b02873] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Ashley P. Mattey
- Manchester Institute of Biotechnology (MIB) and School of Chemistry, The University of Manchester, 131 Princess Street, M1 7DN, Manchester, United Kingdom
| | - William R. Birmingham
- Manchester Institute of Biotechnology (MIB) and School of Chemistry, The University of Manchester, 131 Princess Street, M1 7DN, Manchester, United Kingdom
| | - Peter Both
- Manchester Institute of Biotechnology (MIB) and School of Chemistry, The University of Manchester, 131 Princess Street, M1 7DN, Manchester, United Kingdom
| | - Nico Kress
- Manchester Institute of Biotechnology (MIB) and School of Chemistry, The University of Manchester, 131 Princess Street, M1 7DN, Manchester, United Kingdom
| | - Kun Huang
- Manchester Institute of Biotechnology (MIB) and School of Chemistry, The University of Manchester, 131 Princess Street, M1 7DN, Manchester, United Kingdom
| | - Jolanda M. van Munster
- Manchester Institute of Biotechnology (MIB) and School of Chemistry, The University of Manchester, 131 Princess Street, M1 7DN, Manchester, United Kingdom
| | - Gregory S. Bulmer
- Manchester Institute of Biotechnology (MIB) and School of Chemistry, The University of Manchester, 131 Princess Street, M1 7DN, Manchester, United Kingdom
| | - Fabio Parmeggiani
- Manchester Institute of Biotechnology (MIB) and School of Chemistry, The University of Manchester, 131 Princess Street, M1 7DN, Manchester, United Kingdom
| | - Josef Voglmeir
- Glycomics and Glycan Bioengineering Research Center (GGBRC), College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Juana E. R. Martinez
- Departamento de Biología, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Col. Noria Alta S/N, Guanajuato 36050, México
| | - Nicholas J. Turner
- Manchester Institute of Biotechnology (MIB) and School of Chemistry, The University of Manchester, 131 Princess Street, M1 7DN, Manchester, United Kingdom
| | - Sabine L. Flitsch
- Manchester Institute of Biotechnology (MIB) and School of Chemistry, The University of Manchester, 131 Princess Street, M1 7DN, Manchester, United Kingdom
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17
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A family AA5_2 carbohydrate oxidase from Penicillium rubens displays functional overlap across the AA5 family. PLoS One 2019; 14:e0216546. [PMID: 31091286 PMCID: PMC6519835 DOI: 10.1371/journal.pone.0216546] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 04/24/2019] [Indexed: 12/02/2022] Open
Abstract
Copper radical alcohol oxidases belonging to auxiliary activity family 5, subfamily 2 (AA5_2) catalyze the oxidation of galactose and galactosides, as well as aliphatic alcohols. Despite their broad applied potential, so far very few AA5_2 members have been biochemically characterized. We report the recombinant production and biochemical characterization of an AA5_2 oxidase from Penicillium rubens Wisconsin 54–1255 (PruAA5_2A), which groups within an unmapped clade phylogenetically distant from those comprising AA5_2 members characterized to date. PruAA5_2 preferentially oxidized raffinose over galactose; however, its catalytic efficiency was 6.5 times higher on glycolaldehyde dimer compared to raffinose. Deep sequence analysis of characterized AA5_2 members highlighted amino acid pairs correlated to substrate range and conserved within the family. Moreover, PruAA5_2 activity spans substrate preferences previously reported for AA5 subfamily 1 and 2 members, identifying possible functional overlap across the AA5 family.
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18
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A Novel Colletotrichum graminicola Raffinose Oxidase in the AA5 Family. Appl Environ Microbiol 2017; 83:AEM.01383-17. [PMID: 28778886 DOI: 10.1128/aem.01383-17] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 07/24/2017] [Indexed: 12/17/2022] Open
Abstract
We describe here the identification and characterization of a copper radical oxidase from auxiliary activities family 5 (AA5_2) that was distinguished by showing preferential activity toward raffinose. Despite the biotechnological potential of carbohydrate oxidases from family AA5, very few members have been characterized. The gene encoding raffinose oxidase from Colletotrichum graminicola (CgRaOx; EC 1.1.3.-) was identified utilizing a bioinformatics approach based on the known modular structure of a characterized AA5_2 galactose oxidase. CgRaOx was expressed in Pichia pastoris, and the purified enzyme displayed the highest activity on the trisaccharide raffinose, whereas the activity on the disaccharide melibiose was three times lower and more than ten times lower activity was detected on d-galactose at a 300 mM substrate concentration. Thus, the substrate preference of CgRaOx was distinguished clearly from the substrate preferences of the known galactose oxidases. The site of oxidation for raffinose was studied by 1H nuclear magnetic resonance and mass spectrometry, and we confirmed that the hydroxyl group at the C-6 position was oxidized to an aldehyde and that in addition uronic acid was produced as a side product. A new electrospray ionization mass spectrometry method for the identification of C-6 oxidized products was developed, and the formation mechanism of the uronic acid was studied. CgRaOx presented a novel activity pattern in the AA5 family.IMPORTANCE Currently, there are only a few characterized members of the CAZy AA5 protein family. These enzymes are interesting from an application point of view because of their ability to utilize the cheap and abundant oxidant O2 without the requirement of complex cofactors such as FAD or NAD(P). Here, we present the identification and characterization of a novel AA5 member from Colletotrichum graminicola As discussed in the present study, the bioinformatics approach using the modular structure of galactose oxidase was successful in finding a C-6 hydroxyl carbohydrate oxidase having substrate preference for the trisaccharide raffinose. By the discovery of this activity, the diversity of the CAZy AA5 family is increasing.
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19
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Thomas B, Lu X, Birmingham WR, Huang K, Both P, Reyes Martinez JE, Young RJ, Davie CP, Flitsch SL. Application of Biocatalysis to on-DNA Carbohydrate Library Synthesis. Chembiochem 2017; 18:858-863. [PMID: 28127867 DOI: 10.1002/cbic.201600678] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Indexed: 01/14/2023]
Abstract
DNA-encoded libraries are increasingly used for the discovery of bioactive lead compounds in high-throughput screening programs against specific biological targets. Although a number of libraries are now available, they cover limited chemical space due to bias in ease of synthesis and the lack of chemical reactions that are compatible with DNA tagging. For example, compound libraries rarely contain complex biomolecules such as carbohydrates with high levels of functionality, stereochemistry, and hydrophilicity. By using biocatalysis in combination with chemical methods, we aimed to significantly expand chemical space and generate generic libraries with potentially better biocompatibility. For DNA-encoded libraries, biocatalysis is particularly advantageous, as it is highly selective and can be performed in aqueous environments, which is an essential feature for this split-and-mix library technology. In this work, we demonstrated the application of biocatalysis for the on-DNA synthesis of carbohydrate-based libraries by using enzymatic oxidation and glycosylation in combination with traditional organic chemistry.
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Affiliation(s)
- Baptiste Thomas
- Manchester Institute of Biotechnology and, School of Chemistry, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK
| | - Xiaojie Lu
- Encoded Library Technologies, NCE Molecular Discovery, R&D, Platform Technology & Science, GlaxoSmithKline, 830 Winter Street, Waltham, MA, 02451, USA
| | - William R Birmingham
- Manchester Institute of Biotechnology and, School of Chemistry, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK
| | - Kun Huang
- Manchester Institute of Biotechnology and, School of Chemistry, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK
| | - Peter Both
- Manchester Institute of Biotechnology and, School of Chemistry, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK
| | - Juana Elizabeth Reyes Martinez
- Manchester Institute of Biotechnology and, School of Chemistry, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK
| | - Robert J Young
- Medicinal Chemistry, NCE Molecular Discovery, R&D, Platform Technology and Science, GlaxoSmithKline, GlaxoSmithKline Medicines Research Centre, Stevenage, Hertfordshire, SG1 2NY, UK
| | - Christopher P Davie
- Encoded Library Technologies, NCE Molecular Discovery, R&D, Platform Technology & Science, GlaxoSmithKline, 830 Winter Street, Waltham, MA, 02451, USA
| | - Sabine L Flitsch
- Manchester Institute of Biotechnology and, School of Chemistry, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK
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20
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Toftgaard Pedersen A, Birmingham WR, Rehn G, Charnock SJ, Turner NJ, Woodley JM. Process Requirements of Galactose Oxidase Catalyzed Oxidation of Alcohols. Org Process Res Dev 2015. [DOI: 10.1021/acs.oprd.5b00278] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Asbjørn Toftgaard Pedersen
- Department
of Chemical and Biochemical Engineering, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - William R. Birmingham
- School
of Chemistry, University of Manchester, Manchester Institute of Biotechnology, 131 Princess Street, Manchester, M1 7DN, United Kingdom
| | - Gustav Rehn
- Department
of Chemical and Biochemical Engineering, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Simon J. Charnock
- Prozomix
Ltd, Station Court, Haltwhistle, Northumberland NE49 9HN, United Kingdom
| | - Nicholas J. Turner
- School
of Chemistry, University of Manchester, Manchester Institute of Biotechnology, 131 Princess Street, Manchester, M1 7DN, United Kingdom
| | - John M. Woodley
- Department
of Chemical and Biochemical Engineering, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
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21
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Parikka K, Master E, Tenkanen M. Oxidation with galactose oxidase: Multifunctional enzymatic catalysis. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.molcatb.2015.06.006] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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22
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Pickl M, Fuchs M, Glueck SM, Faber K. The substrate tolerance of alcohol oxidases. Appl Microbiol Biotechnol 2015; 99:6617-42. [PMID: 26153139 PMCID: PMC4513209 DOI: 10.1007/s00253-015-6699-6] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 05/10/2015] [Accepted: 05/15/2015] [Indexed: 11/29/2022]
Abstract
Alcohols are a rich source of compounds from renewable sources, but they have to be activated in order to allow the modification of their carbon backbone. The latter can be achieved via oxidation to the corresponding aldehydes or ketones. As an alternative to (thermodynamically disfavoured) nicotinamide-dependent alcohol dehydrogenases, alcohol oxidases make use of molecular oxygen but their application is under-represented in synthetic biotransformations. In this review, the mechanism of copper-containing and flavoprotein alcohol oxidases is discussed in view of their ability to accept electronically activated or non-activated alcohols and their propensity towards over-oxidation of aldehydes yielding carboxylic acids. In order to facilitate the selection of the optimal enzyme for a given biocatalytic application, the substrate tolerance of alcohol oxidases is compiled and discussed: Substrates are classified into groups (non-activated prim- and sec-alcohols; activated allylic, cinnamic and benzylic alcohols; hydroxy acids; sugar alcohols; nucleotide alcohols; sterols) together with suitable alcohol oxidases, their microbial source, relative activities and (stereo)selectivities.
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Affiliation(s)
- Mathias Pickl
- Department of Chemistry, Organic & Bioorganic Chemistry, University of Graz, Heinrichstrasse 28, A-8010, Graz, Austria
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23
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Expression, purification, and characterization of galactose oxidase of Fusarium sambucinum in E. coli. Protein Expr Purif 2014; 108:73-79. [PMID: 25543085 PMCID: PMC4370742 DOI: 10.1016/j.pep.2014.12.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 12/14/2014] [Accepted: 12/16/2014] [Indexed: 11/01/2022]
Abstract
A gene encoding a galactose oxidase (GalOx) was isolated from Fusarium sambucinum cultures and overexpressed in Escherichia coli yielding 4.4mg enzyme per L of growth culture with a specific activity of 159Umg(-1). By adding a C-terminal His-tag the enzyme could be easily purified with a single affinity chromatography step with high recovery rate (90%). The enzyme showed a single band on SDS-PAGE with an apparent molecular mass of 68.5kDa. The pH optimum for the oxidation of galactose was in the range of pH 6-7.5. Optimum temperature for the enzyme activity was 35°C, with a half-life of 11.2min, 5.3min, and 2.7min for incubation at 40°C, 50°C, and 60°C, respectively. From all tested substrates, the highest relative activity was found for 1-methyl-β-galactopyranoside (226Umg(-1)) and the highest catalytic efficiency (kcat/Km) for melibiose (2700mM(-1)s(-1)). The enzyme was highly specific for molecular oxygen as an electron acceptor, and showed no appreciable activity with a range of alternative acceptors investigated. Different chemicals were tested for their effect on GalOx activity. The activity was significantly reduced by EDTA, NaN3, and KCN.
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24
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Paukner R, Staudigl P, Choosri W, Sygmund C, Halada P, Haltrich D, Leitner C. Galactose oxidase from Fusarium oxysporum--expression in E. coli and P. pastoris and biochemical characterization. PLoS One 2014; 9:e100116. [PMID: 24967652 PMCID: PMC4072685 DOI: 10.1371/journal.pone.0100116] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2013] [Accepted: 05/22/2014] [Indexed: 11/20/2022] Open
Abstract
A gene coding for galactose 6-oxidase from Fusarium oxysporum G12 was cloned together with its native preprosequence and a C-terminal His-tag, and successfully expressed both in Escherichia coli and Pichia pastoris. The enzyme was subsequently purified and characterized. Among all tested substrates, the highest catalytic efficiency (kcat/Km) was found with 1-methyl-β-D-galactopyranoside (2.2 mM−1 s−1). The Michaelis constant (Km) for D-galactose was determined to be 47 mM. Optimal pH and temperature for the enzyme activity were 7.0 and 40°C, respectively, and the enzyme was thermoinactivated at temperatures above 50°C. GalOx contains a unique metalloradical complex consisting of a copper atom and a tyrosine residue covalently attached to the sulphur of a cysteine. The correct formation of this thioether bond during the heterologous expression in E. coli and P. pastoris could be unequivocally confirmed by MALDI mass spectrometry, which offers a convenient alternative to prove this Tyr-Cys crosslink, which is essential for the catalytic activity of GalOx.
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Affiliation(s)
- Regina Paukner
- Department of Food Science and Technology, BOKU-University of Natural Resources and Life Sciences, Vienna, Austria
| | - Petra Staudigl
- Department of Food Science and Technology, BOKU-University of Natural Resources and Life Sciences, Vienna, Austria
| | - Withu Choosri
- Department of Food Technology, Ramkhamhaeng University, Bangkok, Thailand
| | - Christoph Sygmund
- Department of Food Science and Technology, BOKU-University of Natural Resources and Life Sciences, Vienna, Austria
| | - Petr Halada
- Institute of Microbiology v.v.i., Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Dietmar Haltrich
- Department of Food Science and Technology, BOKU-University of Natural Resources and Life Sciences, Vienna, Austria
| | - Christian Leitner
- Department of Food Science and Technology, BOKU-University of Natural Resources and Life Sciences, Vienna, Austria
- * E-mail:
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25
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Solomon EI, Heppner DE, Johnston EM, Ginsbach JW, Cirera J, Qayyum M, Kieber-Emmons MT, Kjaergaard CH, Hadt RG, Tian L. Copper active sites in biology. Chem Rev 2014; 114:3659-853. [PMID: 24588098 PMCID: PMC4040215 DOI: 10.1021/cr400327t] [Citation(s) in RCA: 1138] [Impact Index Per Article: 113.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
| | - David E. Heppner
- Department of Chemistry, Stanford University, Stanford, CA, 94305
| | | | - Jake W. Ginsbach
- Department of Chemistry, Stanford University, Stanford, CA, 94305
| | - Jordi Cirera
- Department of Chemistry, Stanford University, Stanford, CA, 94305
| | - Munzarin Qayyum
- Department of Chemistry, Stanford University, Stanford, CA, 94305
| | | | | | - Ryan G. Hadt
- Department of Chemistry, Stanford University, Stanford, CA, 94305
| | - Li Tian
- Department of Chemistry, Stanford University, Stanford, CA, 94305
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26
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Anasontzis GE, Salazar Penã M, Spadiut O, Brumer H, Olsson L. Effects of temperature and glycerol and methanol-feeding profiles on the production of recombinant galactose oxidase in Pichia pastoris. Biotechnol Prog 2014; 30:728-35. [PMID: 24493559 PMCID: PMC4282061 DOI: 10.1002/btpr.1878] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Revised: 12/23/2013] [Accepted: 01/29/2014] [Indexed: 11/24/2022]
Abstract
Optimization of protein production from methanol-induced Pichia pastoris cultures is necessary to ensure high productivity rates and high yields of recombinant proteins. We investigated the effects of temperature and different linear or exponential methanol-feeding rates on the production of recombinant Fusarium graminearum galactose oxidase (EC 1.1.3.9) in a P. pastoris Mut+ strain, under regulation of the AOX1 promoter. We found that low exponential methanol feeding led to 1.5-fold higher volumetric productivity compared to high exponential feeding rates. The duration of glycerol feeding did not affect the subsequent product yield, but longer glycerol feeding led to higher initial biomass concentration, which would reduce the oxygen demand and generate less heat during induction. A linear and a low exponential feeding profile led to productivities in the same range, but the latter was characterized by intense fluctuations in the titers of galactose oxidase and total protein. An exponential feeding profile that has been adapted to the apparent biomass concentration results in more stable cultures, but the concentration of recombinant protein is in the same range as when constant methanol feeding is employed. © 2014 The Authors Biotechnology Progress published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers Biotechnol. Prog., 30:728–735, 2014
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Affiliation(s)
- George E Anasontzis
- Industrial Biotechnology, Dept. of Chemical and Biological Engineering, Chalmers University of Technology, Gothenburg, SE-412 96, Sweden; Wallenberg Wood Science Center, Chalmers University of Technology, Kemigården 4, Gothenburg, SE-412 96, Sweden
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27
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Affiliation(s)
- Nicholas J. Turner
- School of Chemistry, University of Manchester, Manchester Interdisciplinary Biocentre, 131 Princess Street, Manchester M1 7DN, U.K
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Rannes JB, Ioannou A, Willies SC, Grogan G, Behrens C, Flitsch SL, Turner NJ. Glycoprotein Labeling Using Engineered Variants of Galactose Oxidase Obtained by Directed Evolution. J Am Chem Soc 2011; 133:8436-9. [DOI: 10.1021/ja2018477] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Julie B. Rannes
- School of Chemistry, University of Manchester, Manchester Interdisciplinary Biocentre, Manchester, M1 7DN, U.K
| | - Avgousta Ioannou
- School of Chemistry, University of Manchester, Manchester Interdisciplinary Biocentre, Manchester, M1 7DN, U.K
| | - Simon C. Willies
- School of Chemistry, University of Manchester, Manchester Interdisciplinary Biocentre, Manchester, M1 7DN, U.K
| | - Gideon Grogan
- Department of Chemistry, University of York, York, YO10 5YW, U.K
| | - Carsten Behrens
- Department of Protein and Peptide Chemistry, Novo Nordisk A/S, Maaløv, Denmark
| | - Sabine L. Flitsch
- School of Chemistry, University of Manchester, Manchester Interdisciplinary Biocentre, Manchester, M1 7DN, U.K
| | - Nicholas J. Turner
- School of Chemistry, University of Manchester, Manchester Interdisciplinary Biocentre, Manchester, M1 7DN, U.K
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Deacon SE, McPherson MJ. Enhanced expression and purification of fungal galactose oxidase in Escherichia coli and use for analysis of a saturation mutagenesis library. Chembiochem 2011; 12:593-601. [PMID: 21264996 DOI: 10.1002/cbic.201000634] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2010] [Indexed: 11/08/2022]
Abstract
Galactose oxidase (GO) displays broad primary alcohol substrate specificity and so offers potential for engineering new substrate specificity by directed evolution. Producing variant libraries of sufficient complexity ideally requires expression of functional protein in a host such as Escherichia coli. Wild-type GO is produced by the fungus Fusarium graminiarum and is expressed poorly in E. coli. We introduced silent mutations within codons 2-7 of the mature GO coding sequence to enhance GO translation and have combined these with other expression-enhancing mutations. We selected the best E. coli host strain, autoinduction medium, induction temperature, harvest time and cell lysis procedure to produce active recombinant GO. Although normally secreted by the fungus, we have expressed GO in the cytoplasm of E. coli and have used a C-terminal Streptag II sequences for single-step affinity purification. This resulted in purification of 240 mg of functional GO per litre of shake flask culture. We have generated a saturation mutagenesis library at residue Cys383, known to influence substrate binding, and have used the optimised expression conditions to purify and characterise the resulting enzymes.
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Affiliation(s)
- Sarah E Deacon
- Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
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Ioannou A, Cini E, Timofte RS, Flitsch SL, Turner NJ, Linclau B. Heavily fluorinated carbohydrates as enzyme substrates: oxidation of tetrafluorinated galactose by galactose oxidase. Chem Commun (Camb) 2011; 47:11228-30. [DOI: 10.1039/c1cc13956h] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Spadiut O, Olsson L, Brumer H. A comparative summary of expression systems for the recombinant production of galactose oxidase. Microb Cell Fact 2010; 9:68. [PMID: 20836876 PMCID: PMC2949794 DOI: 10.1186/1475-2859-9-68] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Accepted: 09/13/2010] [Indexed: 10/25/2022] Open
Abstract
BACKGROUND The microbes Escherichia coli and Pichia pastoris are convenient prokaryotic and eukaryotic hosts, respectively, for the recombinant production of proteins at laboratory scales. A comparative study was performed to evaluate a range of constructs and process parameters for the heterologous intra- and extracellular expression of genes encoding the industrially relevant enzyme galactose 6-oxidase (EC 1.1.3.9) from the fungus Fusarium graminearum. In particular, the wild-type galox gene from F. graminearum, an optimized variant for E. coli and a codon-optimized gene for P. pastoris were expressed without the native pro-sequence, but with a His-tag either at the N- or the C-terminus of the enzyme. RESULTS The intracellular expression of a codon-optimized gene with an N-terminal His10-tag in E. coli, using the pET16b+ vector and BL21DE3 cells, resulted in a volumetric productivity of 180 U·L-1·h-1. The intracellular expression of the wild-type gene from F. graminearum, using the pPIC3.5 vector and the P. pastoris strain GS115, was poor, resulting in a volumetric productivity of 120 U·L-1·h-1. Furthermore, this system did not tolerate an N-terminal His10-tag, thus rendering isolation of the enzyme from the complicated mixture difficult. The highest volumetric productivity (610 U·L-1·h-1) was achieved when the wild-type gene from F. graminearum was expressed extracellularly in the P. pastoris strain SMD1168H using the pPICZα-system. A C-terminal His6-tag did not significantly affect the production of the enzyme, thus enabling simple purification by immobilized metal ion affinity chromatography. Notably, codon-optimisation of the galox gene for expression in P. pastoris did not result in a higher product yield (g protein·L-1 culture). Effective activation of the enzyme to generate the active-site radical copper complex could be equally well achieved by addition of CuSO4 directly in the culture medium or post-harvest. CONCLUSIONS The results indicate that intracellular production in E. coli and extracellular production in P. pastoris comprise a complementary pair of systems for the production of GalOx. The prokaryotic host is favored for high-throughput screening, for example in the development of improved enzymes, while the yeast system is ideal for production scale-up for enzyme applications.
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Affiliation(s)
- Oliver Spadiut
- Division of Glycoscience, School of Biotechnology, Royal Institute of Technology (KTH), SE-106 91 Stockholm, Sweden
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Rogers MS, Hurtado-Guerrero R, Firbank SJ, Halcrow MA, Dooley DM, Phillips SEV, Knowles PF, McPherson MJ. Cross-link formation of the cysteine 228-tyrosine 272 catalytic cofactor of galactose oxidase does not require dioxygen. Biochemistry 2008; 47:10428-39. [PMID: 18771294 DOI: 10.1021/bi8010835] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Galactose oxidase (GO) belongs to a class of proteins that self-catalyze assembly of their redox-active cofactors from active site amino acids. Generation of enzymatically active GO appears to require at least four sequential post-translational modifications: cleavage of a secretion signal sequence, copper-dependent cleavage of an N-terminal pro sequence, copper-dependent formation of a C228-Y272 thioether bond, and generation of the Y272 radical. The last two processes were investigated using a truncated protein (termed premat-GO) lacking the pro sequence and purified under copper-free conditions. Reactions of premat-GO with Cu(II) were investigated using optical, EPR, and resonance Raman spectroscopy, SDS-PAGE, and X-ray crystallography. Premat-GO reacted anaerobically with excess Cu(II) to efficiently form the thioether bond but not the Y272 radical. A potential C228-copper coordinated intermediate (lambda max = 406 nm) in the processing reaction, which had not yet formed the C228-Y272 cross-link, was identified from the absorption spectrum. A copper-thiolate protein complex, with copper coordinated to C228, H496, and H581, was also observed in a 3 min anaerobic soak by X-ray crystallography, whereas a 24 h soak revealed the C228-Y272 thioether bond. In solution, addition of oxygenated buffer to premat-GO preincubated with excess Cu(II) generated the Y272 radical state. On the basis of these data, a mechanism for the formation of the C228-Y272 bond and tyrosyl radical generation is proposed. The 406 nm complex is demonstrated to be a catalytically competent processing intermediate under anaerobic conditions. We propose a potential mechanism which is in common with aerobic processing by Cu(II) until the step at which the second electron acceptor is required.
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Affiliation(s)
- Melanie S Rogers
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, USA
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Escalettes F, Turner NJ. Directed Evolution of Galactose Oxidase: Generation of Enantioselective Secondary Alcohol Oxidases. Chembiochem 2008; 9:857-60. [DOI: 10.1002/cbic.200700689] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Rogers MS, Tyler EM, Akyumani N, Kurtis CR, Spooner RK, Deacon SE, Tamber S, Firbank SJ, Mahmoud K, Knowles PF, Phillips SEV, McPherson MJ, Dooley DM. The stacking tryptophan of galactose oxidase: a second-coordination sphere residue that has profound effects on tyrosyl radical behavior and enzyme catalysis. Biochemistry 2007; 46:4606-18. [PMID: 17385891 PMCID: PMC2532978 DOI: 10.1021/bi062139d] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The function of the stacking tryptophan, W290, a second-coordination sphere residue in galactose oxidase, has been investigated via steady-state kinetics measurements, absorption, CD and EPR spectroscopy, and X-ray crystallography of the W290F, W290G, and W290H variants. Enzymatic turnover is significantly slower in the W290 variants. The Km for D-galactose for W290H is similar to that of the wild type, whereas the Km is greatly elevated in W290G and W290F, suggesting a role for W290 in substrate binding and/or positioning via the NH group of the indole ring. Hydrogen bonding between W290 and azide in the wild type-azide crystal structure are consistent with this function. W290 modulates the properties and reactivity of the redox-active tyrosine radical; the Y272 tyrosyl radicals in both the W290G and W290H variants have elevated redox potentials and are highly unstable compared to the radical in W290F, which has properties similar to those of the wild-type tyrosyl radical. W290 restricts the accessibility of the Y272 radical site to solvent. Crystal structures show that Y272 is significantly more solvent exposed in the W290G variant but that W290F limits solvent access comparable to the wild-type indole side chain. Spectroscopic studies indicate that the Cu(II) ground states in the semireduced W290 variants are very similar to that of the wild-type protein. In addition, the electronic structures of W290X-azide complexes are also closely similar to the wild-type electronic structure. Azide binding and azide-mediated proton uptake by Y495 are perturbed in the variants, indicating that tryptophan also modulates the function of the catalytic base (Y495) in the wild-type enzyme. Thus, W290 plays multiple critical roles in enzyme catalysis, affecting substrate binding, the tyrosyl radical redox potential and stability, and the axial tyrosine function.
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Affiliation(s)
- Melanie S. Rogers
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA
| | - Ejan M. Tyler
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA
| | - Nana Akyumani
- Astbury Centre for Structural Molecular Biology & Institute of Molecular and Cellular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Christian R. Kurtis
- Astbury Centre for Structural Molecular Biology & Institute of Molecular and Cellular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - R. Kate Spooner
- Astbury Centre for Structural Molecular Biology & Institute of Molecular and Cellular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Sarah E. Deacon
- Astbury Centre for Structural Molecular Biology & Institute of Molecular and Cellular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Sunita Tamber
- Astbury Centre for Structural Molecular Biology & Institute of Molecular and Cellular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Susan J. Firbank
- Astbury Centre for Structural Molecular Biology & Institute of Molecular and Cellular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Khaled Mahmoud
- Astbury Centre for Structural Molecular Biology & Institute of Molecular and Cellular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Peter F. Knowles
- Astbury Centre for Structural Molecular Biology & Institute of Molecular and Cellular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Simon E. V. Phillips
- Astbury Centre for Structural Molecular Biology & Institute of Molecular and Cellular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Michael J. McPherson
- Astbury Centre for Structural Molecular Biology & Institute of Molecular and Cellular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - David M. Dooley
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA
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